Get the best processed foods that you can, Floating and sinking,(Tetra, Nutra fin etc), and different examples of each (at least four and more if poss). and suppliment with frozen and fresh wherever poss. Try to include live and veg/fruit. If you do, make sure that the food is organic (Less chemical residue) Peeled and washed, (Same again) and varied, small worms are often taken greedily, but remember to wash anything that comes in from the garden, and to take them from an area that has not had chemical treatments (Pestacides,fertilisers etc).
My Clowns (And most of my other fish) L O V E Bananas, Peeled peas / Sweetcorn (husks are a complete B*****D in the fish tank), Cherries, peaches and Kiwi fruit. but try anything and remember the favorites.
If you raise your own live food (Mosquitoe lavae and Daphnia will thrive in absolutely anything) make sure that it is clean and well rinsed before being fed to the fish.
enjoy. and remember to laugh at some of the funnier sights that you'll see.